staging: lustre: fix %.2X versus signed char issue

staging: lustre: fix %.2X versus signed char issue

When char is signed and one of the bytes in lmm happens to have a byte
value above 127, the result of printing that with %.2X will be 8 hex
chars, the first 6 of which are 'F'. Worst case, we'll overrun our
'carefully' allocated buffer.

I didn't have the tenacity to work through the gazillion and seven
layers of macros behind CERROR, but I assume it'll all end at some
function implemented in terms of the kernel's vsnprintf. Use %*phN for
a hexdump. That'll cap the number of dumped bytes at 64. If that's a
problem, the loop could be replaced by "bin2hex(buffer, lmm,
lmm_bytes);".

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>